Can I spin a flat head to plane it?

[Handy Don 13,087]

49 minutes ago, Jeff-C175 said:

 

Why not just place the orbital sander polisher on top of the head and move it around? 

 

 

Flatness. Keeping the sander perfectly aligned with the head would be a challenge.

[Jeff-C175 7,203]

14 minutes ago, Handy Don said:

Flatness. Keeping the sander perfectly aligned with the head would be a challenge.

 

Constantly moving... changing positions regularly?

 

How could that be any different than the uneven pressure your hand may exert on the head?

 

 

[ebinmaine 69,728]

12 minutes ago, Jeff-C175 said:

 

Constantly moving... changing positions regularly?

 

How could that be any different than the uneven pressure your hand may exert on the head?

 

 

 

As long as the piece of material that the head was placed against was flat, you may be okay.

 

The reason I turn my cylinder heads 90° after a certain amount of strokes is to compensate for the uneven hand pressure. 

[lynnmor 7,482]

My experience with belt sander type of head dressing ain't good.  There is an engine builder in my area that I used to dress a pair of 350 Chevy heads on his purpose built sanding machine for heads.  When he was done they looked nice, then I laid them face to face and could read a newspaper between them.  He then milled them properly.

 

[Jeff-C175 7,203]

5 hours ago, Handy Don said:

Flatness. Keeping the sander perfectly aligned with the head would be a challenge.

 

Don, I'm not sure you understood what I meant upon rereading your post.

 

I meant to place the head on the flat plate as usual, but using the orbital to agitate it instead of the Armstrong method.

[Roger R 457]

Anyone ever try bluing the block, then setting the head in place, shifting a bit to transfer bluing to the head, then carefully using an old time scraper to remove the transferred bluing along with a very small amount of metal. Repeat until nothing transfers?  Bluing could be applied to the head if it works better.  I remember skilled craftsman matching machine slides etc in this way.  If done properly you may not have a perfect flat head but the two parts would be a perfect match to one another. 

[Ed Kennell 39,754]

12 minutes ago, Roger R said:

Anyone ever try bluing the block, then setting the head in place, shifting a bit to transfer bluing to the head, then carefully using an old time scraper to remove the transferred bluing along with a very small amount of metal.

Bluing and scraping off high spots is common practice to restore a metal surface  to a known flat granite surface plate.     I wouldn't reccomend scraping a block to a uneven head surface.   Scraping a head to the block could work, but probably not as fast or sucessful  as rubbing on emery cloth.    Especially when done by  us hammer mechanics.   

 

 

[ebinmaine 69,728]

6 hours ago, Jeff-C175 said:

 

Don, I'm not sure you understood what I meant upon rereading your post.

 

I meant to place the head on the flat plate as usual, but using the orbital to agitate it instead of the Armstrong method.

How would you fasten the cylinder head to the orbital?

 

[ri702bill 8,754]

20 hours ago, gwest_ca said:

The outside of the head surface is going to see a lot more abrasive than the inside. Think of it like pulley sizes.

Gary is absolutely correct - it is known as Surface Feet per Minute in the Machining trade. When facing a large piece of round stock in a lathe, I have seen some of the old-time guys make a heavy partial cut - maybe 1/3 of the way in at one speed, stop, increase the speed for the other 2/3rds. The finish cut was at one speed, and was a light cut.

[ri702bill 8,754]

20 hours ago, gwest_ca said:

The outside of the head surface is going to see a lot more abrasive than the inside. Think of it like pulley sizes.

Gary is absolutely correct - it is known as Surface Feet per Minute in the Machining trade. When facing a large piece of round stock in a lathe, I have seen some of the old-time guys make a heavy partial cut - maybe 1/3 of the way in at one speed, stop, increase the speed for the other 2/3rds. The finish cut was at one speed, and was a light cut.

[JoeM 7,886]

The last one I sanded I used the magnum magic marker coloring in the surface to be sanded. As to note the high areas that were being taken off first.

 

Then a straight edge to check, I put a flashlight behind the straight edge and noted the light coming under the edge. 

I do this before I start, many need very little work. And a new head gasket is fairly forgiving.

 

10 hours ago, Ed Kennell said:

Especially when done by  us hammer mechanics.

Bush mechanic types!

A mechanic that works in the bush! 

 

In the words of the Great Mod @stevasaurus "don't overthink this " 

 

[Ed Kennell 39,754]

4 hours ago, ebinmaine said:

How would you fasten the cylinder head to the orbital?

 

I believe Jeffs idea is to use the friction between the head cooling fins and the soft foam pad on the sander to attach the two.   

 

This may even work with a simple vibrating hand sander. 

 

Edited March 28, 2022 by Ed Kennell

[Handy Don 13,087]

12 hours ago, Jeff-C175 said:

I meant to place the head on the flat plate as usual, but using the orbital to agitate it instead of the Armstrong method.

Ah! Yes, clearer now, thank you. 

So making some sort of pad for a random orbital that move the head around. Got it.

[lynnmor 7,482]

If the head is so distorted to require power tools, then have it milled flat, followed by a light amount of lapping.

 

When lapping/sanding, keep your hand pressure on the center of the head and use a figure 8 pattern.

[Jeff-C175 7,203]

6 hours ago, ebinmaine said:

How would you fasten the cylinder head to the orbital?

 

 

I was thinking gravity.  Just press down on the head.  Needs some experimentation, and might not work at all!

[ebinmaine 69,728]

55 minutes ago, lynnmor said:

If the head is so distorted to

 

 1.  require power tools,

 

then

 

2. have it milled flat,

 

followed by a light amount of lapping.

 

When lapping/sanding, keep your hand pressure on the center of the head and

 

3. use a figure 8 pattern.

 

1. I've got two different trains of thought here. I did just get a cylinder head finished up that was the worst warped one I've ever had. Took me a long time but I got it done little by little.

Different side of the same coin, I do have one or two that I'd like to have planed extra for increased compression.

 

 

2.  I agree in principle that it should be machine milled but to have somebody else do the work is just too expensive.

At some point I'm going to buy a belt sander but as I stated previously I don't want to do it for the next few months. I was kind of hoping to come up with some sort of a temporary stop-gap solution.

 

3. I'm seeing that some of us use a figure 8 and some of us use a back and forth, rotate.

 

Can anyone comment on why one would be better than the other? I'm of the back and forth crowd because I know from past experience that I have a severe tendency to put more pressure on one side of the head than the other so even if I was going to go to the figure 8 side, I would still have to rotate the head.

 

 

Just curious to know if anybody has a particular specific reason for doing it the way that they do.....

[Jeff-C175 7,203]

24 minutes ago, ebinmaine said:

going to buy a belt sander

 

Belt sander is always handy for other stuff, buy IMHO not really appropriate for engine work.  MUCH too easy to really mess up an otherwise serviceable head.

MUCH more expensive and limited in use, would be a MILLING MACHINE... that's what ya need!  When you get it set up, let me know, I've got a couple things here that need flattening.  I'll be right up.

 

26 minutes ago, ebinmaine said:

one would be better than the other?

 

I would use ALL methods.  Every which way but loose.  And don't stay on one too long.

 

[lynnmor 7,482]

Using the figure 8 pattern, the head is constantly being introduced to different grains of abrasive, back and forth might have a higher grain cut a groove.  Also, by constantly changing position the head takes on the average of any error or differences in the cutting ability of the sanding surface.

[ebinmaine 69,728]

Just now, lynnmor said:

Using the figure 8 pattern, the head is constantly being introduced to different grains of abrasive, back and forth might have a higher grain cut a groove.  Also, by constantly changing position the head takes on the average of any error or differences in the cutting ability of the sanding surface.

Do you spin the head?

[pacer 3,174]

I'm in the 'hand' method group ..... to my thinking to use any of the mentioned powered tools (belt, disc, orbital, etc) is asking for a more warped than started with. These are aggressive tools and controlling by hand the necessary .... 'finesse'? that is required to get the flatness desired --- well, I just would be very leery.

 

If pushed to use a powered tool, I would choose a large disc sander, say 12" diameter with a fine grit. I have one - a 12" disc spinning at the 3300rpms - and use it often in woodworking and it will EAT some wood---- but?, I might think? I might? be able to control trying a head.

 

Eric is just in a bad situation with hand problems and doing the typical method of flat surface/sandpaper. I am experiencing 'trigger finger" on my right hand middle and ring finger and it certainly gets in the way of some of the tasks I need to perform.

[lynnmor 7,482]

1 hour ago, ebinmaine said:

Do you spin the head?

I just hold it and draw an 8 a number of times, then turn it 90 degrees and repeat.  Do this as often as necessary till the job is done.

[Jrain 276]

If I was in your shoes ,I would also be thinking outside the box , my first thought would be as yours to build a better mouse trap so to speak  ,  May I suggest to start with something like a floor polisher they can be had local for cheep on face book MP or craigslist , those old floor polishers are made very stout , perhaps you can strip it down and incorporate the vitals  it in to a table top, then attach glass or a honed piece or granite for a true flat surface , I can also see making a foot switch from the pull switch handles that already exist for the on off operation of the polisher ,this way you can foot operate on and off  leaving both hand free . call me crazy but I can see it working .  

[clueless 3,075]

On 3/27/2022 at 11:52 AM, RubyCon1 said:

 

I miss Chuck .

[ebinmaine 69,728]

2 minutes ago, clueless said:

I miss Chuck .

I never interacted with him because he was gone a year or more before I showed up. Definitely a lot of value in the old posts. I've used the information in several.

 

 

[clueless 3,075]

8 minutes ago, ebinmaine said:

I never interacted with him because he was gone a year or more before I showed up. Definitely a lot of value in the old posts. I've used the information in several.

 

 

He had a lot of how to post, the best part was the way he explained them, he must be a teacher. He even had me doing some of my own electrical stuff .